GB535884A - Spring balancer - Google Patents

Abstract

535,884. Balancing. CHICAGO PNEUMATIC TOOL CO. March 29, 1940, No. 5700. Convention date, June 27, 1939. [Class 78 (ii)] [Also in Group XXXII] A balancing device for suspending a tool &c. comprises one or more readily detachable helical springs 19 and means for enhancing the safety of the device in use. The spring 19 is contained in a casing 14 attachable by a cover 16 and nuts and bolts 15 to the balancer frame 1, the outer end of the spring being fixed to the face 2 of the frame 1 and the inner end to a sleeve 22 slidable without relative rotary movement on the main shaft 3. The casing 14, or a liner 17 thereto, has a plurality of internal projections 18 which keep the spring 19 from filling the casing when loosened, so facilitating insertion and removal and lessening friction. The suspension cable 13 winds on and off a fusee drum 11 mounted rotatably on the shaft 3, but fixedly adjustable thereon by a worm 23 carried by the drum and gearing with a wheel 24 fixed on the shaft 3. This permits the initial tension of the spring to be altered to suit the load. A gravity retracted latch 25 is provided to hold the drum 11 in position either by hand or automatically when the spring breaks and also to limit the rotary travel of the drum. The drum is furnished with a plurality of internal projections 31 between any two of which the head 30 of the latch 25 can rise and so bring up the drum to a stop after a part turn. Rubber inserts 32 on each side of the latch cushion the blow, and a retaining plate 33 for the inserts assists also in guiding the latch. The manual operation of the latch is effected by a plate 24 the lower end of which surrounds a pin 37 extending from the latch. Lost motion between the latch and the plate 34 allows the latter to be slid by a finger-piece 35 to raise the latch, and to remain stationary, helped by a detent 38, when the latch rises from other causes. Raising of the latch when the spring breaks is effected by contact of the outer band of the spring with the pin 37. The latch is lifted at end positions of the drum rotation by a Geneva stop mechanism, the pin 43 of which is carried by the drum 11 and the slotted side 40 of which is journalled on the frame face 2 and has a stud 41 which bears on the bottom of the latch 25 at the end of each oscillation of the disc. Specification 263,185, [Class 78 (ii)], is referred to.